Suter Science Seminars

Friday, March 20, 2009

4 p.m., Science Center 104

Climate Change and Human Evolution: Evidence from the Fossil Record of East Africa

Anna K. Behrensmeyer, Ph.D.

Biological systems and climate have interacted throughout Earth history, so it is logical to expect that climate played a role in the evolution of our own species, Homo sapiens. In East Africa, a rich fossil record of vertebrates including human ancestors is preserved in geological strata that also contain evidence of ancient climates. Successive layers of lake and land sediments as well as stable isotope signals in micro-organisms, land mammal teeth, and soil precipitates provide evidence for warm-wet and cool-dry climate cycles over tens of thousands to millions of years.

Linking the patterns of climate change to events in human evolution requires accurate geological age determinations and careful assessment of all available evidence. On-land fossil records from different regions of Africa, together with better climate data from marine deep-sea drill cores, are strengthening understanding of climate change over the past 6 million years and how it affected the ecology and behavior our earliest ancestors.

About the Presenter

Anna K. Behrensmeyer, Ph.D.

Anna Katherine “Kay” Behrensmeyer received her doctorate in vertebrate paleontology and sedimentology from the Department of Geological Sciences, Harvard University, in 1973. After post-doctoral positions at UC, Berkeley and Yale Universities and teaching for the Earth Science Board, UC, Santa Cruz, she became a research curator at the National Museum of Natural History in1981. She has published over 130 scientific articles and edited volumes and is recognized as a pioneer in the study of land ecosystems and their fossil record through geological time.

She was selected as one of the 50 most important women scientists in the U.S. by Discover Magazine in 2002. Much of Kay’s career has involved paleontological and geological research in the field and laboratory, with a particular focus on the ecological context of human evolution in East Africa. She also works in modern ecosystems to understand how processes that alter and destroy organic remains affect information preserved in the fossil record. Kay is married to William Keyser, and their two daughters, Kristina (13) and Sarah (11), have accompanied them to the field in Kenya.